Its worse then asking for directions...

[Ca_Silvia]

I can not for the life of me figure out why my motor is losing boost above 5500rpm. Ive checked timing, fuel pressure, boost leaks 1000x over. I thought my butterflies were not working so i disabled them, still no change.

I now have to resort to giving my car to a shop to work this out. I really hate having other people work on my car but i really have no idea were to go from here. Ca18det>Me

[r34 gtr]

Just don't take any crap from this shop.

[Buddyworm]

Wait, I just read your other thread. The stock turbo is ****ing balls dude, mine starts petering out after 5500rpm as well I think. I know it can't push a solid 7psi all the way to redline. And if it's still pulling smoothly and not bucking or stumbling then I'm pretty sure you don't have a boost leak. Just the teeny-tiny stock turbo.

[Ca_Silvia]

I know what you mean, before me turbo would spike to ten then settle to 7 by redline. Now its still spikes to 10 then will drop as low as 4psi by redline. With significantly less power above 5500rpm.

I have all weekend to still work things out but come next week i need to get the car up and running.

[dattodude]

I don't want to sound condescending, but the problem is simple.

Either the turbo can't keep up, or you have a pressure related boost leak.This is typical on crash damaged front mount intercoolers and aftermarket intake plenums...

bypass the intercooler with a simple bit of pipe. and see if it continues.

[boost_boy]

Or pay attention to your wastegate actuator! One of these issues are causing your dilemma, but you got to go the extra mile to eliminate the possibilities.

Dee

[Ca_Silvia]

I never got a chance to bypass the intercooler but i did hook up a MBC to control the boost that way. And it worked, so the actuator must be screwed. All my power came back up top with no other issues.

Problem solved finally!

[RM12577]

i put an hks wastegate on mine as it was having the same problem now it holds 8 psi as high as i want to rev it, bought it off ebay though.... working great still and i think it was like 80 bucks maybe...

[Ca_Silvia]

Weird tha you just happen to reply to this today. While i had the MBC on there in order to see if my problem was in fact boost related. I have since removed it due to wild spiking for day to day driving. Today i ordered my HKS adjustable actuator to replace my fubared one and should have it Friday.

Unfortunatly i miss out on the first event of this year tonight.

[RM12577]

sweet, yea i like the adjustable hks unit, i ran mine at 6 psi for a while then cranked it to 8, keeps me from having to put in a lot of extra stuff to change the boost, prolly going to go to 12 psi or so in the future and run e-85....... love the 105 octane corn going through the engine.... just gotta get some more squirt from the injectors first....